Current-rectifier.



No. 830,924. 4- PATENIED SEPT. 11, 1906. F. PAWLOWSKI. CURRENTREGTIFIER.

APPLICATION FILED NOV. 14, 1904.

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CURRENT-RECHNER.

Specification of Letters Patent.

Patented Sept. 11, 1906.

Application led November 14I 1904. Serial No` 282.696.

To (I/ZZ whom, it may concern.-

Be it known that I, FRANZ PAWLowsKr, a subject of the Emperor ofAustria-Hun ary, residing at Vienna, Austria-Hungary, ave inventedcertain new and useful Im roveinents in Current-Rectifiers, of which t1e following is a specification.

Among the dill'erent rectifier-cells for transforming alternatingcurrents in unidirectional-that is to say` continuous-currents the cellsin which one electrode is formed by an aluminium plate are representinga peculiarclass. The other electrode is then formed by any other metal,presenting to the current when used as anode less resistance thanaluminium, and the intermediate layer is formed by a solution of asaltor by a salt in solid state at ordinary temperature and which musttherefore be heated in order to liquify the said salt by melting thesame when taking the cell in use. 4 When connecting the aluminium plat-eof a cell of the aforesaid kind with the positive pole of a generator ofcontinuous current, the passage of the same is meeting a very highresistance, while a much lesser resistance is interposed to the passageof alternatinlr currents.

A ciharacteristic feature of the rectifier-cell.

forming the object of the resent invention consists in that the layeretween the two electrodes is formed of hemisulfid of cop er, (CUQSJwhich has been prepared in a pecul iar manner. Taking the rectifier-cellin use, the said layer preserves its solid condition, and no supply ofheat is required for starting the rectifier.. The utility of hemisulfidof copper to the purpose specified was concluded from the fact that itis liable to polarization-viz., an electromotoric counterferce isindicatedwhen the ends of a bar consisting of hemisulfid of copper areconnected with a galvanometer after having passed through the bar anelectric current. It has also been found that the resistance of manysuliids is a different one, according to the direction, intensity, andduration of a current passed through them.'

tat, second edition, Vol. 1, page 548.) i l lf a system consisting of analuminium plate, a layer of hemisulid of copper and a fid of copper(CuS) to white heat and casting them into molds is not fit for thebefore-mentioned purpose, because it is a bad conductor at ordinary.temperatures. On the contrary, a suitable preparation is obtained bymelting together sulfur and copper or preferablyl by su jectingsheet-copper of a thickness not exceeding two millimeters to the actionof sulfurous vapors without admission of air for so long a period assuch vapors are absorbed, whereupon the hemisulfid of copper is slowlycooled. In this manner there is obtained a very hard crystallinehemisulfid of copper, reslsting to the action of air and water, whichmelts only at about 1,0000 centigrade, and which is a good conductor ofelectricity. It is to be emphasized that the current is conducted withequal facility at ordinary temperature and in both directions.

The improved rectifier consists of a combination of an aluminiumelectrode and an iron electrode, se arated by an intermediate layer` ofhemisuld of copper. In combining the three different substances formingthe cell it is of essential im ortance that the contact is the closestpossi le. rectifier-cells depends only upon the extent of the surface. fl

l The accompanying drawings represent the object of the presentinvention, Figure 1 showing a'lamelliform, Fig. 2 a tubiform,arrangement of the parts constituting the cell. V3 shows a battery,consisting o four rec t' er-cells. l As shown in Fig. 1, the cellconsists of superposed plates-viz. of an aluminium plate 4, a plate 3 ofhemisulfid of copper of somewhat larger surface, and an iron plate 2,all of which arranged between two littlejboards of wood. The shape inwhich the several substances are employed is of no account. According toFig. 2 they are showing, for example, the shape of tubes.

For practical purposes in order to rectify alternating currents incontinuous currents any convenientnumber of lcells of the kindspecifiedmay be connected in parallel or in series, the efficiency ofthe battery constitutedv in this manner bein proportional to the sum ofthe contact-surfaces of all of the lates. Fi 3 represents a combinationof Thefaciency 0f the IOO our cells o the kind shown in Fi 1, theuppermost aluminium plate 4 an the lowermost iron plate 2 consisting inthis case each of one piece, while the interposed plates belonging tothe cells on the rlght and on the IIO' left are separated by anintermediate airspace 6. l

, By means-'of six or more of the aforesald cells polyphase currents maybe transformed in continuous current. The efficiency of the improvedrectifieris much l of any other apparatus of t s kind hitherto known onthe supposition that the following principles be observed: The extent ofthe contact-surfaces-and the mode of connection must be conformed to theintenslty and to the voltage of the alternatingcurrent to be rectifiedor to those of the contlnuous current to be taken olf, respectively-thatis to say, when the intensity is a. greater one several cells must beconnected in parallel, While when the voltage is a greater one severalcells must be connected in series. With a suitable arrangement oftheapparatus a useful effect of seventy* tol eighty per cent. isobtained, importunate development of heat is obviated, and no controland attendance are required. Evenif the apparatus is in use for severaldays the plates show no physical or chemical change, and 'losses ofsubstance or products 'of electrolytic decomposition do not appear. If,however, the number of cells was not sufcient, considerable flashing ofvamount of current delivere sparks and a lar e development of heat takeplace, whereby te loss of voltage is increased. Besides taking care ofchoosing the suitable number and connection of the cells, .the rectifiermust be formed before starting the same for the first time. For thispurpose the apparatus is connected to an alternating-current circuit ofhigh intensity for so long a period as strong sparking takes place,while the poles for supplying continuous current remain open andunloaded during all this time.

*Even` 1f this arrangement is continued for some days neither loss ofalternating current nor short-'clrcuit takes place.

When the rectifier is formed in the aforesaid manner and when sparkinghas almost ceased, thesupplyof continuous current may begin, preferablyincreasin gradually the to which such increase is permitted may beestablished by the stronger sparking which takes place'between thealumlnium and the hemisuliid of copper electrodes when the said limit isattained at, whereby the loss in vol- 4tage is increased and thedurability of the :330,924...t-5in 'l eater than that The limit up Icate this surface smoothness.

l y subject-matter of the present invention and according to thearrangement shown y 1g. combination of several rectifier-cells in orderto obtain a full and complete rectifying of the current. In Aview of thefundamental experiments it has been found preferable to employ aconnecting metal between the se arate cells composed of aluminium `and a(LluZS plate, some other conductor, excepting onecomposed of aluminium.The working of the c ell is an electrolytic process' carried out bymeans of a dry and solid electrolyte. The molecular properties inherentto the aluminium and to u2S pla for themselves a part quite independentom the electrolysis, as will .be hereinafter more fully set forth. It isof course obvious that in the present instance a layer of aluminium oxdcannot be formed; but, on the contrary, under the influence ofelectrolysis: a layer of aluminium suld will be formed which possessesmore or less insulating properties. Thislayer of aluminiun sulfid will,perhaps, consist .only of Aa thin film, but more probably it willconsist of an exceedingly thin layer of dust or powder.

If it be supposed that the lowermost lefthand cell ofthe fo`ur cellsrepresented by Fig.- 3 for the sake of greater clearness Abe designatedby the reference characters 2a 3 lain contradistinction to the otherreference characters in thisv figure, the alternating current whichenters at 2 will simultaneously meet the upper cell 4 3 2 and on theother hand the lower cell 2el 3a 4a. `At the anode 4a the current uponmeeting a thin layer of AIS will undergo a complete interruption. Thecurrent will thereby be deflected in the direction '2 34 andpass withoutany difficulty, be-

cause it Will meet no insulating layer between 3 and 4. The same processtakes place Ain an exactly analogous manner in the other two cells. Inthese cells also in consequence of the formation of an insulating layerof AIS the current will be driven into the exterior circuit. n

To render the apparatus successful, it is 3 of the drawings, isrepresented as a IOO I LO

necessary that the Working plates have surfaces as smooth as possible,and the expression heretofore noted with respect to the formation of theapparatus is intended to indi- By arranging or havin the surfaces of theplates smooth and para lel to each other as nearly as possible, andconsequently avoidinghigh pressure, an apparatus will be obtained thatwill work in a perfect manner.

` The working of the current-rectifier takes place only at the place ofcontact of the alu- `minium with the CuZS, sothat the second electrodeof the rectier has, properly speaking, no other function but the simpleadmission of current to Cu2S and Al. The products. of decompositionwhich are formed at the first-named place are quite insignificant ISOticles of dust or powder will enter into chemf ical combinations ofdiierent kinds, and these Acombinations Will increase the permeabilityofthe rectifier for the alternating current. It is better to explainthe' phenomena which take place in the rectiying ap aratus by theelectron theory and that the e ectrolysis possesses merely a secondaryand a rather injurious iniiuence and constitutes 'not the reason of thepassage of the current, but rather a phenomenon accompanying the same.

It is well known that in the tension ,series aluminium will stand as oneof the highestpositive conductors, whereas Cu2S is one of the uttermostnegative conductors. With this in view it follows that aluminium willcontain mostly positive ions, which will attract the negative charges,whereas CuZS contains mostly negative ions, which attract the positivecharges; These o posed polar ca pacities of aluminium an CuZS maintainthe potential equilibrium as lon as no unidirectional current has beendisc arged, and -in this respect they present fullythe action of valves.The alternating current remains interrupted, there is no appreciableloss of' current, and both continuous-current poles show a considerabletension at-the terminals.`

This potential e uilibrium is, however, immediately distur ed as soon ascontinuous current is being discharged. This manifests itself in thefollowing manner: During the first initial stage aluminium 'elds to Gu2Sits negative charge very rapid y and without formation of sparks; but inexchange it receives simultaneously reduced copper-dust chargedpositively, and this dust se arated from the CuZS deposits rinly on thea uminium." In the second stage when` aluminium becomes the anode thecop er which has remained deposited on the a uminium is also chargedpositively and combines easily with S (or also with O of the atmosphericair 3) but at the same time it is repelled by the positive charge of thealuminium, since it is also char ed positively, and it ,forms a sparkwhic restablishes the original condition. The other and greater partofthe positive charge at the aluminium forms with the CuzS a very iinelayer of aluminium sulfid, which interrupts the dischagre of any furtherpositive charge to the Cu,S and compelsV the current to take `anotherway. At the next negative charge of the aluminium the reduced particlesof copper positively charged for the exchange meet no longer the purealuminium, but the extremely fine layer of aluminium sulid, and theygive up to it thlei' `charge and are again converted into In theabove-described manner the operations in the current-rectiierare'rapidly repeating themselves with the eifect of a corresponding lossof energy., The above exposition concerning the working of therectiii'er re uires still a very im ortant theoretical ad 'tion'. Theelectro ytical phenomena can be considered as being of a secondarynature and as having injurious effects. The efficacious moment whichmakes the two substances employed, according to .the invention aluminiumand CuQS, particularly suitable for producing in their combination as acell the rectifying of the alternating current lies in the specificmolecular properties of these substances. The 4aluminium saturated withnegative ions effects very easily its exchan e with a ri 'dl -l ositivecharge of rigiovable coppi alioniysm apsimjlar exchan e is renderedossible by easily-se arableust particles o a substance like Cu2 Thepositively-charged aluminiuln has, however, tightly bound the charge tothe substance. Its capacity is rather small for the positive ions, andthe structure is such that a pulverization ispossible only under a veryhigh tension. The giving upgof the charge of the ositive ions finds,therefore, considerable o stacles, which as a rule are overcome onlyunderformation of sparks. CuS presents quite the opposite properties-aconsiderable ca acity for the positive chargel and the fac' 'ty of theeasy dissolution into electrolytical copper atoms which can changetheir-place when the positive charge is lying rigidl Y 1. Acurrent-rectiiier cell having -a solid electrolyte composed of hemisuldof copper.v

2,'Acurr'ent-rectif1er involving two e trode-plates, one of thev latterbeing complosed of aluminium, and a plate of hemisuld of copper arrangedbetween the two electrode-plates.

In testimony whereof I have hereunto set my hand in presence of twosubscribing Witnesses.

. FRANZ PAWLOWSKI.

' Witnesses:

JOSEF RUBAncH,

ALvnsTo S. HoGUE.

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